Is this that big of an issue? I find spam in the hope of some small reward on every social platform. Whether it is Instagram accounts hoping to follow/like people at random in the hope of bringing some % back to their page where they have some affiliate links or products, or Facebook friend requests with links to scams.

Imo, it would be a mistake to trade of any improvement to user experience in the effort to fight abuse. It would be better to lower the barriers of entry as much as possible, to increase user retention as much as possible, and make our "product" easier to understand and use as possible, even if it meant allowing for some more abuse.

We have far bigger problems to solve than any of the worst abuse that our chain is currently experiencing, or has experienced in the past, namely how we can attract, retain and sustain a growing userbase with properly aligned economics to benefit the token value. We can min-max efforts to limit bread crumb farmers after we've solved that.